feat: recognice if the backend is broken

src/autoFetch.ts

@@ -2,13 +2,12 @@ import { DateTime } from 'luxon'
 import { info, debug } from './logger.js'
 import { rabbit } from './rabbit/rabbit.js'
 import staticConfig from './staticConfig.js'
-import fetch from 'node-fetch'
+import heartbeat from './heartbeat.js'
 
 let fetchedHour: number | null = null
 
 export const autoFetch = () => {
-    if (process.env.HEARTBEAT_URL)
-        fetch(process.env.HEARTBEAT_URL)
+    heartbeat()
     const hour = DateTime.now().hour
     if (fetchedHour != hour) {
         fetchedHour = hour

src/heartbeat.ts

@@ -0,0 +1,25 @@
+import { DateTime } from 'luxon'
+import fetch from 'node-fetch'
+import database from './database.js'
+
+const runHeartbeat = async () => {
+    let heartbeatUrl = process.env.HEARTBEAT_URL
+    const newestTrainTrip = await database('train_trip').whereNotNull('destination_station').first()
+
+    if (newestTrainTrip) {
+        const newestTrainTripHour = DateTime.now().diff(DateTime.fromJSDate(newestTrainTrip.timestamp)).as('hours')
+        if (newestTrainTripHour > 6) {
+            console.error('The newest train trip in the database is about 6 hours old. It seem\'s like the backend is broken. Try to restart.')
+            console.error('Heartbeat disabled because the backend seems to broken')
+            heartbeatUrl = undefined // disable heartbeat
+        }
+    } else {
+        console.warn('No full train trip does yet exist in the database')
+    }
+
+    if (heartbeatUrl) {
+        fetch(heartbeatUrl)
+    }
+}
+
+export default runHeartbeat